MOSCOW, May 23. /TASS/. Ukraine has asked Russia for a discounted price by using a null export duty to the year-end, Russia's Minister of Energy Alexander Novak told reporters on Saturday.

"This is an old request, they are asking for the time to the year-end," he said.

The minister replied with a "yes" to a question, whether Ukraine had asked about it officially.

Earlier TASS reported referring to the minister, the decision on discounted gas prices for Ukraine would be made every three months. Mechanisms and discounts are to be agreed quarterly, "depending on the current situation at the moment," the minister said then.